Polychrome television screen and process of manufacture



Dec. 8, 1964 R. GUY 3,160,774

POLYCHROME TELEVISION SCREEN AND PROCESS OF MANUFACTURE Filed May l0, 1961 l2 INVENTOR.

ROGER GUY l/ BY (uw .j l' 57- ATTORNE 3,160,774 Patented Dec. 8, 19,64

s rse '7i/tF rotrcnnoarn retevision SCREEN Ann rnocnss or MANUrAcrnna lRoger Guy, Clamart, France, assignor to Compagnie de Saint-Gobain, Neuilly-sur-Seine, France Filed May 10, 1961, Ser. No. 109,053 Claims priority, application France Apr. 30, 1359 Claims. (Cl. 313-92) This invention relates to polychrome striped screens for use in color television.

It is known that is is possible to reconstitute the color scale by combination of at least three appropriate primary colors. rl`his principle is the basis of the largest part of color television systems, which utilize the principle of splitting up an image into three monochromatic images each of which is in one of three primary, coordinate colors; the three images are transmitted electronically to the receiving screen. Generally these screens are of the polychrome type and are viewed with direct vision. Some of the screens are made bythe dot stippling of pin-point elementary surfaces onto a transparent support and others are made by the application to the support of parallel stripes. Dots and stripes are generally made of uorescent substances which emit, under the impact of an electronic beam, a light which is colored according to that one color of the primary colors in the screen which is found in the particular dot or stripe. The parallel stripes are preferable to the stippled surfaces, both for their luminous eiliciency and for easier manufacture.

It is also possible to use screens constituted by a iilm of pigments with white homogeneous luminescence, in front of which is placed a conveniently colored optical filter. ln the tubes for color television used until present time, a striped colored iluorescent screen is laid down on the bottom of the tube and at a Very short distance of the screen a grid is set, whose wires are in a rigorously determined position in relation to the stripes of the screen. The practical application of these grids and their placing in the receiver tubes are delicate operations as the wires have in particular a tendency to distend under the iniiuence of temperature changes during the mounting of the tube and during its use.

These drawbacks can be partially avoided by binding the wires of the grid to the screen, but the correct positioning of the wires remains a diiiicult problem.

It is an object of this invention to prepare a superior television tube which is eliicient and presents less of a problem of manufacture. Another object is to do away with the 'control larnents which have been used between the colored triads in some'construction. Another object is to supply a superior tube useful without alteration in systems suchV as the de France system of French Patents 664,080 and 1,087,363. Another object is to prepare tubes for use with color which are equally useful in black and white transmission. Other objects will appear as the description proceeds.

The objects are accomplished, generally speaking, by a television tube having a transparent polychrome screen comprisingv a transparent objective plate, a series of opaque, parallel bands applied to the plate at equal intervals, a continuous, conductive, transparent layer coating the plate and said opaque bands, colored plurads composed of parallel stripes in compatible colors carried by the said conductive layer, arranged in alignment with the spaces between the opaque bands and exposing strips of the conductive layer above the opaque bands, and a white, luminescent layer covering the plurad groups, and by a method of making such tubes by the application of stripes of enamels, a layer of transparent metal or metal oxides, stripes of colored enamel, and a layer of white luminescence.

The tube face, target, or objective is preferably glass but may be composed of any transparent material having adequate strength, for instance quartz.

The opaque enamels applied to the tube face are electrically non-conductive, are applied in thin stripes spaced apart the width of a triad, or plurad as the case may be, and are baked on.

Over the opaque enamel stripes and the Wholeruseful face of the tube is applied a layer of transparent conductive material of which metal oxides or metal are pref enamels in alignment with the spaces between the opaquev strips. AThese triads are composed of contiguous, non-l conductive stripes of enamel Veach stripe of which is colored by a different colored pigment, the colors being compatible, and primary. The continuous conductive coat is exposed between the triads over the opaque stripes and the exposed part serves the purposes of a conductive lament. Y

` The stripes may all be of the same size, for instancey 0.4 mm. in width. They may be applied by any known method, such as by the silk screen and oilset processes, which are well able to apply such line lines in parallelism and contiguously.

Over the colored triads is applied a layer of White luminescence of any known type, all of which are useful, both thoser previously used with color and those used with blackand white projection.v

The above and further objects and novel features of the present invention will more fully appear from the following detailed description when the same is read in connectionwith the accompanyingdrawings. It is to be expresslyunderstood, however, that the drawings are for the purpose of illustration only and are not intended as a definition of the limits of the invention, reference for this latter purpose being had primarily to the appended claims.

In the drawings, wherein like reference characters refer to like parts'throughout the several views,

FlG. l is a perspective view, partly cut away, showing a section, A, taken out of the face of a television tube;

FIG. 2 is an enlargement of section A, diagrammatically presented; and v FG. 3 is a perpendicular section, on enlarged scale, through' 'the face of a television ltubeY such as that of FlG. 1.

Referring to the numerals of the drawing, a television Vtube 10, vhaving a glass face 11, is provided at spaced intervals, on its inner face, with opaque stripes 12 which extend in straight, parallel lines'across the whole target area; ofthe colored stripes of the triads, for instance 0.4 mm. and they are composed of low melting enamels containvThe opaque stripes of 0.4 mm. width are appliedto the y This conductive layer is slightly elevated overv These stripes may be of the same widthas each 3 face .of the tube in parallel and equally spaced lines separated by spaces of 1.2 mm. in width across the inner face of a television screen. The stripes are applied by known methods as offset, silk screen, etc.

After the opaque enamel stripes Vhave been applied to the tube face, the tube face is baked at a temperature on the order of about 550 C. whichfpermanently sets the stripes.

The hot ltube face then receives a conductive layer ofV transparent metal oxide or metal for example a mixture vof stannous oxides or stannous and antimonium oxides. Useful examples of the conductive layer are tin, antimony, indium, cadmium and their oxides. The tube face must be baked before spraying to about 40G-450 C. Typical Aconductive mixtures are:

The solution is preferably applied .while the tube face is l still hot from the baking of the opaque enamel stripes and cooled to said temperature of about M26-450 C. A thin metallic film 13 forms over and coversthe' inner face of the plate 1l, including the opaque stripes 12. This layer Vis electrically conductive and the portions 13', elevated above the stripes y12, perform the function that was pre-Y viously performed by the wires of the conductive grid. In

the other embodiments the wires had to be joined togethenwhereas according to'our inventiony the unitary nature of the metallic layer obviates that difficultyV and provides a better structure. 1

The layer 13 is transparent, but the Vopaque stripes 12, beneath the conductive stripes t3', stop the rays Athat might pass through those lines, so that only the raysY from the triads are seen.

YThe triads are three enamel stripes, for instancenlfftfor red, 1S for green, and le for blue, applied between the elevated stripes 13. Stripes 13', 14, 15, and 16 are cond tiguous. Stripes 13 is part of the conductive layer 13, but Y stripes 14, 15, 16 are non-conductive, colored enamels.

The enamels are vitriied, as are also the opaque enamels,

Vat a temperaturev of about lG-550" C. after they have been applied. The triad enamels may befcomposed of low melting pointrvitreous enamels having for example the following composition: Y

Percent Y Y VPercent SiOZ 3.4 A1203- 2.2 Naz() 0.4 Pb0 Y, 53Y B203 l 25 BaO 16 The coloration may 'be obtained by means clifSe-l-SCdy (for red), VC00 (for blue), Cr203 with or without copperY oxide or cobalt oxide for green color.

Y n transparent.

`After the enamels are appliedV manually ortby silk i screen or other'satisfactory methods theplateis Vagain baked at the fusing temperature of the enamels, about SOO-559 C. Aand cooled. To this'plate is addedoverV the triads, a white luminescent layer 17 of ordinaryconstitution containing ZnS and/or CdS and activators..

These compositions are known, are on the marken'I and l the different activators as wellfas'the compositions ,arey

.in the' sales literature of the manufaci .-a solution-of sodium silicatefollowed by heating torabout 4&0 C. during 2() minutes. 1

. i? y A particular advantage of this invention lies in the substitutionl of the novel continuous conductive layer for the wire gridror prior constructions. Another advantage is the enamelled constitutionV of the tube face and the permanence resulting therefrom. Another advantage arises from the fact that any enamels softening below thel softening temperature of the glass of the tube face can be used, which gives a very wide selection of compositions.

The invention may be summarized as follows: Existing tubes have fluorescent, colored, lined screens in which the colored lines are applied to the faceplate of the tube, adjacent to which is a grill having its wires in position rigorously xed by the linesof thescreen. Those wire grills are a source of difficulty by reason of their tendency to warp. They can be made .better by fixing them in place against the screen but they remain a source of difculty as it is hard to attach them accurately.

The present invention is ofthe type having a white luminescent layer over a'tricolored lined lter, and is characterized by a grill constituted by a continuous, transparent, conductive layer applied to the` glass of the tube face, upon which are disposed at equal intervals, the transparent and non-conductive colored triads, exposing'between adjacent Vtriads strips of the conductive layer which act as elements of the grill and which are adapted to be in alignment with the control rays ofthe tube. An opaque stripe is mounted on the tube plate immediately under each exposed conductive stripe in order to mask the white light, unfiltered, which enters the exposed conductive stripes.

i Theftransparent conductive layer may advantageously consist of a very thin metallic or metalroxide vfilm, which are placed, after theplate of the tube has received the opaque stripes. v VThese stripes maybe obtained by the Vprocess cited there above Vorby all known processes.

V,The opaque bands and colored triads are composed of enamels containing appropriatey pigments to supply the opacity or the color as the case may be. In order to assure the electrical isolation of the zones covered by the triads, the colored stripes of each triad are made contiguous.l

A major advantage of the invention is the elimination of the metallic grid and the elimination of the labor and difiiculty of making electrical connections between all the elements of the metallic grid.V Y

In the practical application vof the invention, one applies to the glass which is to form the target of the tube, its face plate, with precise spacing, black enamel stripes by offset, orl by silk screen techniques, which have this capacity and do not need description. The black enamel ystripes are baked at temperatures which x them to the glass, then, without letting the glass cool, one sprays a mixture of anhydrous stannic chloride, antimony chloride, and formaldehyde Vin ethyl alcohol onto the plate, the reduction proceeds and deposits a metallic or metal oxide iilm, and eventually dry the coat, which is conductive and I The triads Vare then applied inV accordance with prior practice, taking car-e to leave between each pair lof triads a spaced aligned with the stripes'of black enamel.

Y ln considering the drawings of this case it should be realized that they are diagrammatic and are not intended to be.` anaccurate representation of form, proportion, or

d from the spirit and scope thereof, it is to be understood that the invention is notl limited to the specific embodiments.

What is'claimed is: A, Y

l. AVcathode rayscreen having a transparent polychrome screen comprising a transparent objective plate,

a'series of opaque, parallel Abands applied toV the plate at equal intervals, a continuous, conductive, transparent layer coating the plate and said bands, colored plurads composed of parallel stripes in compatible colors carried by said conductive layer, arranged in alignment with the spaces between the opaque bands and exposing stripes of the conductive layer above the opaquebands, and a white, luminescent layer covering the plurad groups.

2. A cathode ray screen having a transparent polychrome screen comprising a transparent glass objective plate, a series of opaque, parallel, non-conductive enamel bands applied to the plate at equal intervals, a continuous,

conductive, transparent layer coating the plate and said I bands, colored triads comprising three coordinate primary colors composed of parallel, non-conductive enamel stripes carried by said conductive layer, arranged in alignment with the spaces between the'opaque bands and exposing stripes of the conductive layer above the opaque bands, and a white luminescent layer covering the triads and the exposed parts of the conductive layer.

3. A cathode ray screen according to claim 2 in which the conductive layer is metal.

4. A cathode ray screen according to claim 2 in which the conductive layer is metal oxide.

5. A cathode ray screen according to claim 2 in which the triads are composed of non-conductive enamel stripes in three primary colors.

6. A cathode ray screen according to claim 2 in which the conductive coat comprises tin.

7. A cathode ray screen according to claim 2 in which the conductive coat comprises tin and antimony.

8. A cathode ray screen according to clann 2 in which the conductive coat comprises tin oxide. Y

9. A cathode ray screen according to claim 2 in which the conductive coat comprises tin and antimony oxide. l

10. A cathode ray screen according to claim 2 in which the conductive coat comprises indium.

ll. A cathode ray screen according to claim 2 in which the conductive coat comprises indium oxide.

12. A cathode ray screen according to claim 2y in which the conductive coat comprises cadmium.

13. A cathode rayk screen according to claim 2 in which the conductive coat comprises cadmium oxide.

14. A'method of making a television tubewhich comprises applying to the glass face of a tube evenly spaced stripes of opaque, non-,conductive enamel, baking the enamel, coating the glass face of the tube evenly with a solution of a reducible metal salt and a reducing compound while the glass is at moderately elevated temperature, thereby coating the glass and spaced stripes with a transparent, conductive coat, applying tricolor triads of non-conductive enamel in alignment with the spaces between the opaque stripes, leaving the conductive coat exposed over the opaque stripes, and baking the enamel, and applying to the face of the tube, over the triads, a luminescent white coating.

15. A manufacturing process of a color television screen, consisting in laying down on the bottom of the tube evenly spaced stripes of black opaque enamel, baking said enamel, covering the whole area of the said bot- Atom surface with a continuous conducting transparent layer, and laying down isolating trichromous juxtaposited transparent stripes, covering the whole said bottom area with a uniform layer of luminescent white pigments.

16. A manufacturing process of a color television screen, consisting in laying down on the bottom of the tube evenly spaced opaque stripes, covering the whole area of the said bottom surfaceV with a continuous conducting transparent layer, chromous transparent stripes over the areas between the said opaque stripes, and covering the Whole said bottom area with a uniform layer of luminescent white pigments.

17.v A manufacturing process of a color television screen, consisting in laying down on the bottom of the tube evenly spaced stripes of black opaque enamel, baking said enamel, spraying the whole area of said bottom surface v with a solution of reductible metallic salt and reducing compound while the glass of the said bottom surface has not yet cooled, obtaining through the reduction of the said metallic salt a uniform transparent conducting' iilm covering the whole bottom area of the tube, laying down transparent insulating juxtaposited stripes of enamels of three different colors, so as to cover the areas between the said black stripes, and covering the whole said bottom area with a uniform layer of luminescent white pigments.

18. A color television receiver tube comprising a plurality of opaque parallel stripes disposed at predetermined intervals on the inner surface of the target face of said tube, a transparent conductive layer having a lower surface disposed over said opaque stripes and said intervals, a plurality of parallel predetermined colored stripes, said predetermined colored stripes being disposed on the upper surface of said conductive layer between and parallel to said opaque stripes in composite coloring groups,

said conductive layer having portions disposed between 'l said groups, and a luminescent layer having a lower surface adapted to cover said colored stripes and said portions at the upper surface of said conductive layer disposed between said groups. .v

19. A screen adapted to intercept an electron beam to provide a composite color image thereon, said screen comprising a transparent layer7 a plurality of opaque'parallel stripes disposed at predetermined intervals on the surface of said transparent layer, a transparent conductive layer having a lower surface disposed over said opaque stripes and said intervals therebetween, a plurality of parallel predetermined colored stripes, said predetermined colored stripes being disposed,V on the upper surface of said conductive layer between and parallel to said opaque stripes in composite coloring groups, said conductive layer having portions disposed vbetween said groups, and a luminescent layer having a lower surface adapted to cover said colored stripes and said portions at the upper surface of said conductive layer disposed between said groups.

20. A method of making a color television receiver tube which comprises disposing on the inner surface of the target face of said tube a plurality of parallel opaque stripes in a predetermined fixed relationship covering said opaque stripes and said intervals therebetween with' the lower surface of a transparent conductive layer, disposing on the upper surface of said conductive layer parallel predetermined colored stripes, said colored stripes being arranged in composite coloring groups and parallel to' and 'Y between said opaque stripes, portions of said conductive layer being disposed between said groups and disposing a luminescent layer over said groups and said portions of said conductive layer.

References Cited in the tile of this patent UNITED STATES PATENTS la ing down kisolating tri- Feldman 4. 'Aug. 29, 1961 

18. A COLOR TELEVISION RECEIVER TUBE COMPRISING A PLURALITY OF OPAQUE PARALLEL STRIPES DISPOSED AT PREDETERMINED INTERVALS ON THE INNER SURFACE OF THE TARGET FACE OF SAID TUBE, A TRANSPARENT CONDUCTIVE LAYER HAVING A LOWER SURFACE DISPOSED OVER SAID OPAQUE STRIPES AND SAID INTERVALS, A PLURALITY OF PARALLEL PREDETERMINED COLORED STRIPES, SAID PREDETERMINED COLORED STRIPES BEING DISPOSED ON THE UPPER SURFACE OF SAID CONDUCTIVE LAYER BETWEEN AND PARALLEL TO SAID OPAQUE STRIPES IN COMPOSITE COLORING GROUPS, SAID CONDUCTIVE LAYER HAVING PORTIONS DISPOSED BETWEEN SAID GROUPS, AND A LUMINESCENT LAYER HAVING A LOWER SURFACE ADAPTED TO COVER SAID COLORED STRIPES AND SAID PORTIONS AT THE UPPER SURFACE OF SAID CONDUCTIVE LAYER DISPOSED BETWEEN SAID GROUPS.
 20. A METHOD OF MAKING A COLOR TELEVISION RECEIVER TUBE WHICH COMPRISES DISPOSING ON THE INNER SURFACE OF THE TARGET FACE OF SAID TUBE A PLURALITY OF PARALLEL OPAQUE STRIPES IN A PREDETERMINED FIXED RELATIONSHIP COVERING SAID OPAQUE STRIPES AND SAID INTERVALS THEREBETWEEN WITH THE LOWER SURFACE OF A TRANSPARENT CONDUCTIVE LAYER, DISPOSING ON THE UPPER SURFACE OF SAID CONDUCTIVE LAYER PARALLEL PREDETERMINED COLORED STRIPES, SAID COLORED STRIPES BEING ARRANGED IN COMPOSITE COLORING GROUPS AND PARALLEL TO AND BETWEEN SAID OPAQUE STRIPES, PORTIONS OF SAID CONDUCTIVE LAYER BEING DISPOSED BETWEEN SAID GROUPS AND DISPOSING A LUMINESCENT LAYER OVER SAID GROUPS AND SAID PORTIONS OF SAID CONDUCTIVE LAYER. 